Travis Brenden (QFC Associate Director) recently co-authored 4 papers with colleagues from the Michigan State University Aquatic Animal Health Laboratory on viral hemorrhagic septicemia virus genotype IVb (VHSV-IVb) disease dynamics in the Great Lakes region and the potential of using vaccination to protect fish against outbreaks of the virus. VHSV-IVb is an emerging sublineage of VHSV with a wide host range that quickly spread throughout the Great Lakes watershed and caused multiple large fish die offs. In the first paper (Throckmorton et al. 2017), potential reservoirs of VHSV-IVb were examined in Budd Lake, a Michigan inland lake that is considered enzootic for the virus. VHSV-IVb was detected in multiple samples of amphipods both in 2011 and 2012, but was not detected in Notropis spp., Lepomis spp., mussels, leeches, or water samples, suggesting that amphipods might serve as a reservoir or vector for the virus. In the second paper (Millard et al. 2017), a DNA vaccine containing the glycoprotein gene of VHSV-IVb was developed and evaluated in its ability to protect muskellunge, which is a species that is highly susceptible to the virus, against infection. The relative percent survival of immunized muskellunge when challenged with the virus was 45%. In a follow-up paper (Standish et al. 2016a), relative percent survival of immunized muskellunge when challenged with VHSV-IVb increased to 100% when vaccinated individuals were given a booster dose and allowed a longer incubation period prior to the challenge. In the fourth paper (Standish et al. 2016b), a laboratory study was conducted to determine whether a herd immunity response, which is a necessary precursor for a vaccination program to be successful, could be elicited in fish. The study used a novel flow-through tank design in which different combinations of naïve and immunized muskellunge housed in tanks were exposed to VHSV-IVb via infected muskellunge housed in a tank supplying water to the other tanks. The mortality of naïve muskellunge on average was lower when co-occurring with immunized muskellunge than when naïve muskellunge were housed alone (36.5% when co-occurring with vaccinated muskellunge versus 80.2% when housed alone), indicating a possible protective effect based on cohabitation with vaccinated individuals. Travis and QFC Post-Doctoral Research Associate, Lori Ivan, have recently completed a modeling project using the information learned from the Standish et al. (2016b) study to determine the feasibility of vaccinating and stocking hatchery-propagated fish as a means to protect a wild fish population again viral outbreak. They hope to publish this research soon. Travis and Lori will be giving presentations on their modeling results at two upcoming meetings: American Fisheries Society Fish Health Section meeting and the International Association of Great Lakes Research annual conference.
Millard, E.V., S.E. LaPatra, T.O. Brenden, A.M. Bourke, S.D. Fitzgerald, and M. Faisal. 2017. DNA vaccination partially protects muskellunge against viral hemorrhagic septicemia virus (VHSV-IVb). Journal of Aquatic Animal Health 29:50-56. (see here)
Standish, I.F., E.V Millard, T.O. Brenden, and M. Faisal. 2016a. A DNA vaccine encoding the viral hemorrhagic septicemia virus genotype IVb glycoprotein confers protection in muskellunge (Esox masquinongy), rainbow trout (Oncorhynchus mykiss), brown trout (Salmo trutta), and lake trout (Salvelinus namaycush). Virology Journal 13:203; doi:10.1186/s12985-016-0662-8. (see here)
Standish, I.F., T.O. Brenden, and M. Faisal. 2016b. Does herd immunity exist in aquatic animals? International Journal of Molecular Sciences 17:1898; doi:10.3390/ijms17111898. (see here)
Throckmorton, E., T. Brenden, A. Peters, T. Newcomb, G. Whelan, and M. Faisal. 2017. Potential reservoirs and risk factors for VHSV IVb in an enzootic system: Budd Lake, Michigan, United States. Journal of Aquatic Animal Health 29:31-42. (see here)